This document summarizes the use of bacterial biocontrol agents for managing plant diseases. It discusses three important bacterial species - Bacillus subtilis, Pseudomonas fluorescens, and Pseudomonas aeruginosa. For each species, it provides the taxonomic classification and describes their morphological characteristics. It also outlines their modes of action, which includes production of antibiotics, siderophores, and inducing systemic resistance in plants. Several studies demonstrating the effectiveness of these bacteria in reducing plant diseases are summarized through tables and figures. The document concludes that bacterial biocontrol agents can offer an ecofriendly and cost-effective strategy for plant disease management.

1. 11

2. Dr. Shikha Sharma (Assistant Professor)
COA, Balaghat,JNKVV, Jabalpur, MP (India)

3. INTRODUCTION
BIOLOGICAL CONTROL
MODE OF ACTION
o Siderophore production
o Antibiotic production
o Induced systemic resistance
BIOLOGICAL CONTROL of
PLANT DISEASES
o Bacillus subtilis
o Pseudomonas fluorescens
o Pseudomonas aeruginosa
CONCLUSION
FUTURE THRUST
CONTENTS
33

4. INTRODUCTION
4

5. The indiscriminate and extensive use of pesticides in recent
years has possed a serious problem of pollution in the eco-system and
development of resistance in the pathogens.
In this context, biological control strategy of the pest
management has been found ecofriendly, less expensive and offer
marketable products free of hazardous chemicals.
Many genera belonging to fungi, bacteria, actinomycetes and
viruses are used as a biocontrol agent to combat several important
plant diseases.
My seminar focus only on the efficacy of bacterial biocontrol
agent in the management of plant diseases.
5

6. “The reduction of inoculum density or disease producing
activities of a pathogen or parasite in its active or dormant
state, by one or more organisms, accomplished naturally or
through manipulation of the environment, host or
antagonist or by mass introduction of one or more
antagonist.”
Baker and Cook , 1974
What is biological control?
66

7. Indian Phytopathology
Journal of Mycology and Plant Pathology
Fig : 1 Research papers, 2005-2008
7

8. CHARACTERISTICS OF IDEAL BIOCONTROLCHARACTERISTICS OF IDEAL BIOCONTROL
AGENTSAGENTS
 It should grow fast.
 It has un-damaging nutrient and environment requirement.
 It should be good at primary resource capture to colonize
organic, new plants and seedling.
 Isolation and culturing them should be easy.
 It should be non pathogenic to plants, humans and
domestic animals.
 It should be stress tolerant.
 It should have capacity to parasitize more than one pathogen.
8
88

9. Better seedling emergence
Enhance seed germination
Improve root system
Increase plant growth and development
Increase plant yield
Reduce plant diseases
Inexpensive
Environmentally safe 9

10. Bacteria Fungal Pathogens Host Plant Environment
Pseudomonas sp. Fusarium oxysporum f. sp.
lycopersici
Tomato Rock wool
P. aureofacience 63-
28
P. aphanidermatum Cucumber Vermiculite
P. chlororaphis
MA342
Drechslera graminis Barley Soil
P. Chlororaphis PCL
1391
Fusarium oxysporum f. sp.
lycopersici
Tomato Soil
Pseudomonas putida F. oxysporum f. sp. raphani Radish Soil/Sand
P. fluorescens BTP7 Pythium aphanidermatum Cucumber Vermiculite
P. putida BTP1 Pythium aphanidermatum Cucumber Vermiculite
Table 1. Bacteria applied to seeds or roots as biocontrol of
fungal plant pathogen
Wellesbourne (UK) Whipps (2001)
10

11.  Antagonism
 Antagonist
 Antibiosis
11

12. Antibiotic productionAntibiotic production
Siderophore productionSiderophore production
Induced systemic resistanceInduced systemic resistance
12

13. 13

14. Antibiotic produced play a vital role in antagonist and pathogen
interaction leading to disease suppression. Certain strain of bacterial
antagonist produce diffusible secondary metabolite that inhibit other
bacteria and fungi.
BACTERIA SECONDARY METABOLITE
Pseudomonas fluorescens
 2, 4 Diacetylphloroglucinol
 Sorbisitin Al & B
 Pyrrolnitrin
 Pyoluteorin
 Oomycin A
Pseudomonas aeruginosa  Pyoluteorin
 HCN
Bacillus sp.  Surfactin
 Kanasamine
14

15. COCH3
OH
OHHO
CH3CO
OH
OH Cl
Cl
O
NH
2,4-Diacetylphloroglucinol
Pyoluteorin
Cl
Cl
NHNO2
Pyrrolnitrin
COOH
OHN
N
Phenazines
FIG. 2: Structure of antibiotic produced by bacterial bioagents
15

16. 16

17. Bacterial bioagents produces water soluble fluorescent
siderophore, which act as high-affinity iron chelators that inhibit the
growth of fungi and bacteria through iron deprivation under iron
limited condition. As siderophore sequester the limited supply of iron in
the rhizosphere, they limit its availability to pathogens and ultimately
suppress their growth.
Bacteria Siderophore
Pseudomonas fluorescens Ferribactin
Ferrichrome
Ferroxamine B
Pseudobactin
Pyochelin
Pseudomonas aeruginosa Pyoverdine
17

18. 18

19. Induction of resistance by bacterial bioagents is
mainly through the production of :
Phytoalexins
PR-proteins
Salicyclic acid
Peroxidases
19

20. Fig.:3 Interaction between plant growth promoting rhizobacteria
(PGPR), plant pathogens and soil. ISR = Induced systemic resistance
2020

21. 2. Pseudomonas
IMPORTANT SPECIES OF BACTERIAL BIOAGENTS UTILIZED FOR
BIOCONTROL OF PLANT DISEASES
 Bacillus subtilis
 B. cereus
 B. lichenformis
 P. fluorescens
 P. putida
 P. aeruginosa
 P. alcaligens
 P. aureofaciens
 P. cepacia.
1. Bacillus
21

22. BIOLOGICAL CONTROL OFBIOLOGICAL CONTROL OF
PLANT DISEASESPLANT DISEASES
2222

23. Bacillus subtilis
23

24. Kingdom Protista
Phylum Fermicutes
Class Bacilli
Order Bacilliales
Family Bacillaceae
Genus Bacillus
Species subtilis
Binomial name Bacillus subtilis
Table 2 Taxonomic position of Bacillus subtilis
24

25.  Bacillus subtilis is Gram
positive, rod shaped
and endospore forming
aerobic bacteria.
 Bacillus subtilis
forming colonies that
are dull colored and
may be wrinkled cream
to brown.
Endospore
Vegetative
cell
Fig. 4 cells of Bacillus subtilis
25

26. Treatments Nodules /plant Root rot incidence
(%)
30 DAS 45 DAS
Seed treatment with Rhizobium alone
@ 600g/15 kg of seeds
8.7 16.1 100.0
(90.0)
Seed treatment with Bacillus subtilis @
600g/15 kg of seeds
0.0 0.0 42.5
(40.7)
Seed treatment with Rhizobium
+Bacillus subtilis @ 600g each /15kg of
seeds
10.7 20.0 37.5
(37.5)
Carbendazim @ 2g/kg of seed. 0.0 0.0 67.5
(55.2)
Control 0.0 0.0 100
(90.0)
CD 0.5 0.9 13.0
(Figure in partheses are transformed values)
DAS- Days after sowing.
TNAU (Coimbatore)
Table : 3 Interaction of Bacillus subtilis and Rhizobium on nodulation and root rot
incidence of urdbean under pot condition.
26

27. Fig. 5: Damping off of Tomato 27

28. Treatments Damping off
(%)
Population of antagonists(× 107
c.f.u./g soil)
Fruit
Yield
(kg)/ plot
B. subtilis Str. Ch-br-b2 6.0 27.3 3.97
B. subtilis Str. Ch-G-D4-1 4.8 99.0 4.20
B. subtilis Str. Gr-RCA-b-1 14.2 35.7 2.93
B. subtilis Str. Ch-M-b-1 2.7 64.3 4.05
Streptomyces sp. Str. cot-coi-b-1 5.4 15.3 5.92
Neem formulation 2 (seed treatment +
drenching, 2l/plot)
3.3 -- 4.00
Neem formulation 3 (seed treatment +
drenching , 2l/plot)
3.7 -- 4.16
Metalaxyl( 0.625%) (seed treatment +
drenching, 2l/plot)
5.8 -- 4.33
Control 18.0 -- 3.48
LSD( P= 0.05) 10.4 -- 2.33
Table : 4 Effect of seed treatments with biocontrol agents and neem based
formulations in management of damping off of
tomato under pot condition .
Based on four replication.* Mean value of two runs of the field trial. Arc sine % transformed values.
Udaipur (Rajasthan) Bohra and Mathur ( 2005) 28

29. Fig. 6 In vitro interaction between Bacillus subtilis (B246) with F.
solani showing bulb formation and release of cell
contents( 400 × mag)
29

30. A B
Fig. : 7 In vitro interaction between B. subtilis (B246) and
Colletotricum gloeosporiodes showing
(A) Control germination of Colletotricum gloeosporiodes
(B) Germination in the presence of the antagonist (400 ×
mag)
30

31. Fig. : 8 In vitro interaction showing B. subtilis (B246) being
attracted to the germinating fungal spore and
subsequent polar attachment of the bacteria to the
fungal surface (400 x mag.)
31

32. Treatment Mycelial growth in diameter (cm) Inhibition
(%)
Gliocladium virens 3.2 64.1
T. reesi
4.5 50.4
T.harzianum 5.0 44.4
T. longibrachiatum 5.4 40.0
T.viride 1.5 83.3
P.fluorescens strain-1 5.0 44.4
B. subtilis 1.3 85.5
control 9.0
-
CD(P=0.05) 0.05
Table : 5. In vitro efficacy of antagonists against the growth of Alternaria solani
TNAU (Vallanad) Vadivel and Ebenezar (2006) 32

33. Bacterial species Mean inhibition (%) Antagonism index**
B. subtilis - A 20.0 Weak+
B. subtilis - B 00.0 Nil
B. subtilis - D 00.0 Nil
B. subtilis - G 78.5 strong
Fluorescent
pseudomonad
17.9 Weak
Streptomyces - I 00.0 Nil
Streptomyces – II 14.6 Weak
Streptomyces – III 20. 0 Weak
Control - Nil
CD (P= 0.05)20.0 2.4 _
Table : 6 Antagonism of bacterial antagonist to Alternaria alternata inciting
blight of sesame ( 7d of incubation at 28±⁰c) under in vitro condition
Figure were arcsine transformed before analysis
Junagadh ( Gujarat) Akbari and Parakhia (2007) 33

34. 34
Pseudomonas fluorescens

35.  Gram -ve.
 Straight to curved
rod
shaped.
 Motile by one or
more
flagella.
 Strict anaerobes.
 Producing
fluorescent
pigment.
Fig. :9 Plate of Pseudomonas fluorescens
35

36. Kingdom Protista
Phylum Probacteria
Class Gamma Probacteria
Order Pseudomonadales
Family Pseudomonaceae
Genus Pseudomonas
Species fluorescens
Binomial name Pseudomonas fluorescens
Table 7. Taxonomic position of Pseudomonas fluorescens36

37. Seed treatment Per cent germination Per cent seedling infection
Inoculation
with
Post inoculation
bacterization with
I II I II
Treatments
X. axonopodis CRb – 9 66 (54.33)a
63 (52.33)a
45.0 (42.13)a
47.3(43.49)b
X. axonopodis CRb – 14 63 (52.53)a
60 (50.77)b
52.6 (46.52)b
55.5 (48.15)b
X. axonopodis CRb - 17 70 (56.79)b
66 (54.33)c
38.0 (38.06)c
40.0 (39.23)c
X. axonopodis CRb – 26 76 (60.67)c
70 (56.79)d
21.6 (27.80)d
28.5 (32.26)d
X. axonopodis CRb – 39 73 (58.69)d
66 (54.33)c
31.8 (43.32)e
35.5 (36.27)e
Control
X. axonopodis ------- 56 (48.45)e
53 (46.72)e
76.4 (60.94)f
68.0 (55.82)f
CD (P = 0.05) Within 1.91 1.02 1.30 0.69
Between 1 and 2 2.70 1.84
I = sterilized soil condition and II = unsterilized soil condition, values followed by same
letter in a column are not significantly different at 5% level. Data in parentheses are arc
sine transformed values
CRb - 9 and 14 = P. alcaligenes, CRb – 17 = P. putida, CRb – 26 and 39 = P. fluorescens
IARI ( New Delhi ) Mondal et al. (1993)
Table : 8 . Effect of various P. fluorescens strain on improvement in seed
germination and reduction of seedling blight of cotton
37

38. .Fig. : 10 The gac A two-component system of P. fluorescens strain CHA0 makes an
essential contribution to biocontrol.
38

39. Fig.: 11 Pseudomonas fluorescens treated cucumber on right showing
protection against bacterial wilt of cucurbits.
39

40. Table : 9. Effect of antagonist on seed germination and onion
basal rot incidence under pot condition.
Seed Treatment
@ 4g/kg of seed
Percent
germination
(%)
Percent disease incidence
(DAS)
15 30 40 60
T. Viride 78.00
(62.14)
28.45
(32.16)
36.00
(36.84)
42.45
(40.66)
45.68
(42.52)
T. harzianum 73.00
(58.77)
33.45
(33.56)
43.15
(40.91)
48.53
(44.14)
50.68
(45.27)
P. fluorescens 67.00
(54.97)
36.98
(37.38)
46.70
(43.10)
52.08
(46.19)
54.23
(47.26)
Bacillus subtilis 55.00
(47.88)
55.80
(48.34)
45.53
(54.05)
70.00
(56.75)
72.05
(58.10)
T. viride + P.
fluorescens
88.00
(69.86)
16.30
(23.38)
24.90
(30.00)
29.20
(32.68)
31.35
(34.04)
Contd.
40

41. T. harzianum+ P. fluorescens 80.58
(63.85)
24.38
(29.55)
31.90
(34.38)
36.20
(37.00)
38.35
(38.26)
Bacillus subtilis +T. viride 60.76
(51.20)
37.60
(37.81)
50.60
(45.34)
57.00
(49.06)
61.35
(51.56)
Bacillus subtilis + T. harzianum 58.00
(49.61)
44.60
(41.60)
55.40
(48.10)
61.55
(41.68)
65.85
(54.24)
Control 38.00
(38.05)
75.00
(60.02)
84.67
(67.00)
92.20
(73.90)
94.35
(76.25)
CD (P= 0.05) 4.06 2.87 1.76 0.67
Figure in the parenthesis are arcsine values.
DAS = Days after sowing
TNAU (Coimbatore) Rajendran and Rangnathan (1996)
41

42. Treatment
Growth of F. oxysporum
(mm)
Growth reduction
over control(%)
P. fluorescens strain 1 23.00 55.33
P. fluorescens strain 2 27.25 47.09
P. fluorescens strain 3 29.50 42.72
P. fluorescens strain 11 32.25 37.38
B. subtilis 31.50 38.83
control 51.50
CD (P=0.05) 3.82
Table : 10 Efficacy of bacterial antagonists against F. oxysporum f. sp
cepae under in vitro condition.
*After 5 days of inoculation
TNAU, Coimbatore Rajendran and Rangnathan (1996)
42

43. Treatment Germination
(%)
Disease incidence*
(%)
Yield of green
rhizome (t/ha)
Mulching (dry) 88.78 21.88 (27.85) 20.31
Mulching (wet) 92.58 16.02( 21.39) 26.39
Mulching (dry)+ neem
cake @ 1kg/m
84.37 26.02(31.07) 19.92
Mulching (wet) )+
neem cake @ 1kg/m
81.25 30.47(32.88) 19.12
Mulching (wet) + seed
bacteriazation 10
cfu/ml
92.58 7.42 (14.94) 29.42
Control 85.94 21.10( 26.98) 19.51
CD (P=0.05) NS 11.28 6.30
Figure in parentheses are arcsine transformed value.
KAU (Kerala) Anith et al. (2000)
43

44. Treatment No. of nodules /plant Root rot
incidence(%)
Grain yield kg/ha
ST- PF 1 47.53b
29.7abcd
1086f
ST + SA- Pf 1 58.60e
25.1a
1238h
SA- Pf 1 50.50bcd
28.9abc
1125g
ST- Carbendazim 47.26b
32.8bcd
1023e
ST + SD- Carbendazim 54.20d
27.6ab
1205h
SD - Carbendazim 48.26bc
39.4cd
727b
ST –Pf 1 + SD-Carbendazim 52.33d
35.6d
830c
ST- Carbendazim + SA – Pf-1 51.60cd
31.5bcd
968d
control 38.86a
55.8e
458a
ST-seed treatment ( Pf 1= 10g/kg of seed) and (carbendazim= 2g/kg of seed); SA- soil application=
2.5kg/ha ; SD- soil drenching ( 0.05%).
In a column, mean followed by the same letters do not differ significantly (P= 0.05) by DNMRT.
TNAU (Coimbatore) Jayashree et al., (2000)
44

45. A B
C
Fig. 12: DUAL CULTURE METHOD
A = Pseudomonas fluorescens
B = P. aeruginosa
C = Control (Macrophomina phaseolina) 45

46. P. fluorescens
(strain)
Source of isolates Location Percent inhibition over control
Black gram Sesame
Pf 1 Blackgram Coimbatore 82.6 i 84.5 h
Pf ko 1 Pepper Kodaikanal 36.5 c 38.3 c
Pf BS 1 Paddy Bhavanisagar 23.3 a 21.5 a
Pf ATR 1 Tapioca Attur 40.7 d 42.8 d
Pf MDU 1 Paddy Madurai 51.8 f 48.6 e
FP 7 Paddy Trivandrum 75.3 h 73.1 g
Pf NA 1 Banana Namkkal 47.3 e 53.4 f
Pf NL 1 Forest trees Nilgiris 30.4 b 33.2 b
Pf KO 2 Pepper Kodaikanal 57.3 g 55.9 f
Pf RA 1 Carrot Rajapalayam 21.7 a 20.4 a
ln a column, means followed by the same letter do not differ significantly (P = 0.05) by Duncan’s multiple range test.
TNAU (Coimbatore) Jayashree et al.(2000) 46

47. Endophytic bacterial isolates Percent
growth
inhibition on
PDA
Percent growth
inhibition on TSA
Fungal
radial
growth (sq.
mm) on PDA
Fungal radial
growth (sq.
mm) on TSA
P. fluorescens (PDBCEN 1) 30.32 (32.44) 44. 97 (38.38) 40.20 26.40
Pseudomonas sp. (PDBCEN 2) 26.02 (31.12) 35.76 (48.98) 42.70 30.66
Bacillus subtilis (PDBCN 3) 37.93 (31.59) 20.94 ( 38.15) 35.86 37.86
Pseudomonas sp. (PDBCN 4) 29.05 (30.52) 35.89 (34.60) 40.93 30.60
Endophyte (PDBCN 5) 21.64 (36.36) 52.22( 41.50) 45.23 22.90
Pseudomonas sp. ( PDBCN 6) 22.46 (25.21) 43.39(43.03) 44.70 26.83
Endophyte (PDBCN 7) 35.88 (27.98) 49.11( 47.77) 37.00 24.33
Pseudomonas sp. (PDBCN 8) 24.10 (39.47 ) 34.42 (41.88) 43.03 30.03
Bacilllus sp. (PDBCN 9) 34.12 (28.20) 39. 79 (40.50) 38.03 28.70
Pseudomonas sp. (PDBCN 10) 29.75 ( 36.90) 48.28(39.29) 40.60 24.86
Control 0 0 57.75 47.93
CD (P=0.05) 3.47 8.14 1.92 4.51
Figure in parentheses are angular transformed values
JNKVV (Jabalpur) Rangeswaran et al.(2002) 47

48. Fig. : 13 Collar rot of Chickpea
48

49. Treatment
Percent disease incidence
(mean)
1999 2000
P. fluorescens CP8-2 @ 10 8
cfu/ml/seed 66.4 94.7
P. fluorescens CP8-3 @ 10 8
cfu/ml/seed 73.0 88.9
thiram 3.0 g 97.0 82.1
P. fluorescens CP8-2+ CMC o.1 % +
thiram 1.5g/kg of seed
76.4 64.7
P. fluorescens CP8-3 + CMC o.1% +
thiram 1.5g/ kg of seed
57.6 64.8
control 95.6 88.9
SE ± 8.5 5.2
Patancheru (A.P.) Singh et al.(2003)
Table:15 Effect of Pseudomonas fluorescens strains and thiram on the
incidence of chickpea collar rot in green house during 1999 – 2000.
49

50. Sr.
No.
Treatments Seed
infection (%)
Germination
(%)
Root
length
(cm)
Shoot
length
(cm)
Vigour
index
1 B. subtilis isolate
9 @ 10g/kg.
14.25abc
(22.00)
90.75b
(72.44)
24.90b
13.98ab
3531cd
2 P. fluorescens
isolate 10 @
10g/kg.
10.75a
(18.91) 92.25b
(74.81)
25.45b
15.90b
3756d
3 T. viride isolate 3
@ 10g/kg.
18.0abc
(25.02) 92.00b
(73.70)
21.08a
13.25ab
3163bc
4 Carbendazim @
2g/kg
12.75ab
(20.79)
89.25b
(71.08)
21.53a
11.33a
2934b
5 Control 51.00d
(45.62) 69.00a
(56.47)
20.63a
12.50ab
2305b
Figures in the parentheses are arc sine transformed values.
Mean followed by a common letter are not significantly different at the 5% level by DNMRT.
TNAU (Coimbatore) Gopalkrishnan and Valluvaparidasan (2006)
Table : 16 Effect of selected biocontrol agents and fungicide on Sarocladium
oryzae seed infection, seed germination and seedling characters of
ADTRH-1
50

51. Bioagents Dose
(g/l)
Disease severity
(%)
Disease incidence
(%)
Grain yield
(kg/ha)
2001 2002 2001 2002 2001 2002
Pfr 5 2.0 46 53 75 79 6909 6352
4.0 43 52 71 73 7027 6537
8.0 37 40 64 70 7226 6769
Pfr 1 2.0 46 48 78 75 6995 6454
4.0 37 41 72 71 7149 6603
8.0 34 36 60 63 7370 6855
Check 77 87 95 95 5583 5183
CD (P=0.05)
Bioagents 1.21 1.2 1.0 2.0 2.0 166.7
Rates 1.7 1.5 2.4 2.8 235.7 261.7
Interaction 2.4 2.1 3.0 4.0 333.4 369.4
Figure were angular transformed before analysis
GBPUAT (Pantnagar) Singh and Sinha (2007)
51

52. Fig. 14 Root rot of Chickpea 52

53. Table:18 Effect of farm yard manure, mustard cake and vermicompost (soil
application) and P. fluorescens (6g/kg) seed on root rot incidence in chickpea
Treatment Farmyard manure Mustard cake vermicompost
Dose
(g/kg
soil)
Root rot
incidence
Colonies
(x10 /g
soil)**
Dose
(g/kg
soil)
Root rot
incidence
Colonies(x
10 /g soil)
**
Dose
(g/kg
soil)
Root rot
incidence
Colonies(x
10 /g soil)**
30 d 60 d 30 d 60 d 30 d 60 d
PFBC-25
+ FYM
5 36.7
(60.7)*
17.3 15.6
7
1 32.2
(65.5)*
20 18.7 5 37.8
(59.5)*
17.7 15
10 29.9
(69.1)
25 22 2 21.5
(77.0)
28.3 25.3 10 28.9
(69.1)
26 23
20 23.3
(75.0)
28.7 26.7 3 20.0
(78.6)
32 28.7 20 22.2
(76.2)
28 25.3
PFBC-26
+ FYM
5 37.89
(59.5)
16.3 14 1 33.3
(64.3)
21.3 17.7 5 35.9
(61.5)
19 16.7
10 31.1
(66.7)
23.7 21 2 23.3
(75.5)
27.3 24.3 10 26.7
(71.4)
25 24
20 24.4
(74.9)
27.7 26 3 20.7
(78.1)
30 25.7 20 20.0
(78.6)
29.3 25
CONTROL
93.3 - 93.3 - 93.3 - -
CD (P=
0.05)
9.5 2.2 1.6 7.9 1.8 1 8.8 1.7 1.6
CV(%) 13.7 5.2 4.2 12.3 3.8 2.5 13.1 4 4.1
Figure in parentheses represent disease control (%); **population of P. fluorescens in unamended and
untreated control was 2 and 3x10 g soil at 30 and 60 DAS, respectively.
Bikaner (Rajasthan) Khan and Gangopadhyay (2008) 53

54. Antagonist Dose (g/kg
seed)
Root rot
(%)*
Disease
control (%)
Colonies** (×10 10
/g soil)
30 d 60 d
PFBC- 25 4
6
8
50.0
40.0
36.7
48.3
58.6
62.1
8.0
14.3
17.7
11.0
17.3
20.3
PFBC-26 4
6
8
48.5
38.15
34.4
49.8
60.5
64.5
7.3
15.0
18.3
10.7
16.7
19.7
Control - 96.7 96.7 - -
CD (P= 0.05) 8.8 8.8 1.3 1.5
CV (%) 10.8 10.8 5.6 5.3
*Figures were angular transformed before analysis;
**population of P. fluorescens in untreated control was 1 and 2× 10 /g soil at 30 and 60 DAS, respectively
Bikaner (Rajasthan) Khan and Gangopadhyay (2008) 54

55. Fig. : 15 (A ) : Arabidopsis plant infected with the pathogen Pseudomonas
syringae shows typical yellowing and disease symptoms (control)
(B) : Roots were treated with the bacterium Bacillus subtilis.
A B
55

56. 56
Pseudomonas aeruginosa

57. Kingdom Protista
Phylum Probacteria
Class Gamma Probacteria
Order Pseudomonadales
Family Pseudomonaceae
Genus Pseudomonas
Species aeruginosa
Binomial name Pseudomonas aeruginosa
Table: 20 Taxonomic position of Pseudomonas aeruginosa
57

58.  Gram-negative
 Rod shaped
 0.5 to 0.8 μm x
1.5 to 3.0 μm
 Motile (single
polar flagellum)
A
C. Plate of P. aeruginosa
B. Cell of P. aeruginosa
A. Broth culture of P. aeruginosa
Fig. : 16 A, B and C 58

59. Karachi (Pakistan) Anjaiah et al. (1998)
Fig. : 17. Biocontrol of Fusarium oxysporum f. sp. ciceris on chickpea JG 62 grown in naturally infested soils
with seed treatmentment with strain PNA1 and mutants FM29 and FM13. Values are means of
five replications. Data represented by bar with the same letter do not differ significantly
according
to Fisher’s least significant difference (LSD) test at P = 0.05.
59

60. Treatment
Root knot index
Infection %
M. Phaseolina F. solani
Pumpkin
control 3.1 87 56
P. lilacinus (PL) 1.2 94 44
P. aeruginosa (PA) 0.6 50 19
PL + PA 0.5 19 19
Guar
CONTROL 4.1 31 75
P. lilacinus (PL) 3.5 6 62
P. aeruginosa (PA) 2.0 19 44
PL + PA 1.4 6 37
Chilli
Control 3.3 31 75
P. lilacinus (PL) 2.9 19 56
P. aeruginosa (PA) 2.5 12 75
PL + PA 2.1 12 69
Watermelon
CONTROL 3.8 62 69
P. lilacinus (PL) 2.8 69 81
P. aeruginosa (PA) 1.5 25 69
PL + PA 1.5 37 44
L. S. D. P= 0.05 0.34 6.1 6.1
Table:21 Effect of Pseudomonas aeruginosa and Paecilomyces
lilacinus in the control of root rot diseases of some vegetable
Karachi (Pakistan) Parveen et al. (1998) 60
Soil application of P. lilacinus 2.5ml 10 7
cfu/ml and P. aeruginosa 2.5 ml 10 8
cfu/ml

61. Fig. : 18. Stem rot of Groundnut
61

62. Bacterial strain Habitat Plant mortality
(%)
Biomass of S.
rolfsii
(mg)b
GGS 12 Geocarposphere 81.3±4.6 296.7±12.5 (41)
GPS 21 Phylloplane 75.0±2.7 315.7±18.9 (37)
GPS 38 Phylloplane 81.3±3.9 268.7±21.8 (46)
Pseudomonas sp. GRS 175 Rhizosphere 66.7±4.0 268.7±21.8 (46)
GRS 223 Rhizosphere 72.9±5.3 142.6±8.7 (71)
GSE 3 Seed 89.6±5.3 257.9±15.9 (48)
GSE 5 Seed 79.2±9.7 267.9±12.9 (46)
GSE 6 Seed 87.5±3.0 337.2±23.7 (32)
P. aeruginosa GSE 18 Seed 45.8±2.7 276.8±21.9 (45)
P. aeruginosa GSE 19 Seed 41.7±2.8 128.9±9.7 (74)
GSE 21 Seed 87.5±5.0 140.4±6.7 (72)
P. aeruginosa GSE 30 Seed 68.8±5.7 152.6±7.0 (69)
Control 100.0±0.0 161.5±10.9 (68)
LSD (P = 0.01) 9.7 28.7 9.7 498.5±35.9
Table: 22 Biological control of stem rot disease of groundnut by selected groundnut
associated bacterial strains and their effect on the growth of Sclerotium rolfsii
in dual culture
ICRISAT (Hydrabad)
62

63. Fig. : 19 Bacterial blight of Chilli 63

64. Treatments PDI* Yield
(q/ha)
Recovery of P.
aeruginosa
from
rhizosphere (x
10 7
cfu/g)**
VC + P. aeruginosa + CMC + mannitol as seed treatment @ 10g/
g of seed
20.6 69.6 11.5
VC + P. aeruginosa + CMC + mannitol as root treatment @ 1kg/ 2l
of water
17.4 71.5 34.8
VC + P. aeruginosa + CMC + mannitol as soil application @ 10g mix
with 100 g FYM at transplanting
15.4 74.8 45.2
VC + P. aeruginosa + CMC + mannitol as seed treatment + root
treatment + soil application at transplanting
12.8 85.5 51.9
VC + P. aeruginosa + CMC + mannitol as seed treatment + root
treatment+ soil application at tranplanting + soil application at
30 DAT
8.7 87.3 58.9
Untreated control 94.5 7.8 0.5
CD (P= 0.05) 6.10 4.10 0.12
*Percent disease incidence Angular –transformed before analysis;
** logarithm-before analysis; VC= vermicompost 100g/bag; P. aeruginosa = 10ml (108
cfu/ml; CMC = Carboxy methyl cellulose (1ml @ 1%); mannitol (3ml @
3%).
Table : 23 Effect of substrate based formulation of P. aeruginosa on bacterial
wilt of chillies
Jorhat (Assam) Bora and Deka (2008) 64

65. LIMITATION OF BIOLOGICAL CONTROL
It is slow process as complex interaction involved in
control.
Lack of funds.
Lack of knowledge of factors which determine survival
and colonization of the pathogen and antagonist are
some of the limitation for quick adoption of the
technology.
65

66. Biocontrol agent Target pathogen products
Bacillus subtilis Corticium invisum, C. theae Biotok
Pseudomonas fluorescens Numerous fungal diseases Biocure-B
Bioshield
Plant biocontrol
Agent-2
A. radiobacter strain K84 A. tumefaciens Diegall
Galltrol
Norbac 84c
A . radiobacter k1026 A. tumefaciens, A. rhizogenes No Gall
Bacillus subtilis Strain GB 03 Pythium ultimum, Rhizoctonia solani,
Fusarium spp. and others Pythium spp.
Kodaik
Companion
B. cepcia Pythium spp. Deny
Pseudomonas fluorescens WCS
374r
F. oxysporum f. sp. raphani, F. o xysporum f. sp.
dianthi, E. amylovora
Biocoat
P. fluorescens strain A 506 Alternaria brassicicola, F. oxysporum spp. &
other soil born pathogens
Blight Ban
Streptomyces griseovirdis strain
K61
Sclerotinia sclerotiorum, S. minor, Pythium spp. Mycostop
66

67. Fig .: 20 Products of bacterial
bioagents
A. Bacillus subtillis B. Pseudomonas fluorescens
67

68. Bacterial bioagents are potential bioagents which act against various
fungal, bacterial and nemic diseases.
The bacterial bioagents used alone and in combination with fungicides,
amendments, fungal bioagents have given better disease control and
resulted into better yield.
The bacterial bioagents have helped in better germination and plant
growth, besides disease suppression.
Therefore, bacterial bioagents have been found as primary component in
integrated crop management of soil borne and certain other aerial
fungal plant pathogens.
CONCLUSIO
N
68

69.  Effective strains of Pseudomonas fluorescens,
Pseudomonas aeruginosa and Bacillus subtilis for
disease management under variable conditions
should be identified.
 Suitable agronomic practices need to be evolved for
enhance growth and development of bacterial
bioagents.
 Application of biotechnological tools to improve
biocontrol efficiency of the agents.
FUTURE THRUSTFUTURE THRUST
69

70. 70